1. Field of the Invention
The present invention relates to therapeutic beds and, more particularly, to therapeutic beds of the type having an air cushion support together with an integral fluidized bead surface.
2. Background
The care of patients requiring extensive recuperative periods presents many extraordinary challenges which have not been adequately addressed in the past. Not the least of these challenges is providing a patient support surface that is both sturdy and easy to use, while simultaneously providing preventive therapy and intervention for the numerous complications associated with extended confinement to bed. Burn victims, for instance, typically require extremely low patient interface pressures, high air flow, as well as low shear forces. It is well-known in the art that two of the most ideal patient support surfaces for the immobile patient are low-air-loss beds and fluidized bead beds. Low-air-loss bed and mattress examples are described in U.S. Pat. Nos. 5,005,240 (KINAIR) and 5,022,110 (FIRSTSTEP). Examples of bead beds are described in U.S. Pat. Nos. 4,564,965 (CLINITRON), 5,008,965 (FLUIDAIR), and 5,036,559 (ELEXIS).
Conventional bead beds typically include a bathtub-like tank filled with medical-grade silicone microspheres (or xe2x80x9cbeadsxe2x80x9d). Each individual bead typically has a soda-lime core encased within a silicone sphere approximately 100 microns in diameter. A diffuser board is positioned horizontally at the base of the tank, separating two compartments within the tankxe2x80x94an upper compartment which contains the beads and a smaller, lower compartment which serves as a plenum chamber filled with air for fluidizing the beads. With appropriate blowers and temperature control systems, air is blown into the plenum chamber, from which the pressurized air is forced upwardly through the diffuser board and further (often in bubble-like manner) through the beads, giving the beads a liquid-like quality. A filter sheet is draped over the top of the tank to contain the beads while allowing the upward passage of air. The patient can lie either directly on the filter sheet or on a second cover sheet. Despite the liquefied state of the beads, the patient remains buoyant because of the relative density of the beads.
Although such bead beds may actually provide the most therapeutic surface from the standpoint of pressure and microclimate at the patient interface (i.e., interface between patient and mattress), conventional bead beds have many drawbacks. Traditionally, bead bed manufacturers have thought that a significant depth of beads was required in order to provide an adequate patient support with good fluidization. Fluidizing the resulting volume of beads inherently required heavy-duty blowers and related equipment, not to mention the extra structural requirements for the frames of such beds. Conventional bead beds are extremely heavy (approximately 2,000 pounds), which not only makes them difficult to maneuver, but also requires that they be used only in buildings having extremely sturdy support. Second-story placement in wood-frame houses is typically avoided without assessment by a structural engineer. The poor maneuverability and excessive weight may also present risks to caregivers who are not properly trained in safely maneuvering such heavy objects.
Handling a patient in a conventional bead bed is also plagued with difficulty, largely because caregivers must reach down into the tank and lift the patient up or out for handling. The teaching of U.S. Pat. No. 5,008,965 attempted to address this situation by providing separate air bladders within the bead compartment for displacing the beads upwardly, hence, lifting the patient relative to the tank. Still others, such as illustrated in U.S. Pat. No. 5,036,559 (ELEXIS), have attempted to address the problem by providing deflatable or otherwise collapsible tank walls instead of the traditionally rigid walls. Related difficulty is faced by the patient who is attempting to sit up in such beds. Although foam wedges and the like are often used to help prop up the patient, props present the obvious downfall of interfering with the therapeutic benefits of the bead surface. Using props also renders such products more difficult to manipulate than conventional hospital beds which have automatic bed functions such as head-up, Trendelenberg and the like.
Air beds, on the other hand, eliminate many of these problems. Not only are the mattresses of the air beds lighter due to the lighter supporting medium (i.e., air versus beads), but lighter-duty supportive equipment and structural members are needed as well. Moreover, air beds permit many of the user-friendly features of standard hospital beds, such as sit-up, Trendelenberg, and the like, not to mention retractable side rails and radioluminescence. The extra space beneath the patient surface also allows not only for extra storage, but also for adding accessory therapeutic units such as percussion and hyper-hypothermia treatment.
Many other advantages and disadvantages of low-air-loss beds and air fluidized bead beds will be understood by those of ordinary skill in the art, especially after reviewing this specification.
It is a fundamental object of the present invention to improve over the prior art, including to provide a therapeutic patient treatment bed and related methods which facilitate the care and comfort of bed-ridden patients, while simultaneously addressing the complications associated with immobility.
This and other objects are addressed by providing a therapeutic patient treatment bed wherein the patient support surface comprises an air cushion with integral fluidized bead surfaces. The beads may be fluidized by the same air flow as is utilized for inflating the patient support air cushion. Unlike many prior bead beds, the invention described herein allows the patient support surface to be positioned as desired, providing a lightweight, full-featured fluidized bead bed. Moreover, because air flow can be compartmentalized into a plurality of air bags or cushions, each with independent bead surfaces, the present invention also enables a wide variety of additional surface therapies not previously available with bead beds, including pulsation, percussion, and kinetic therapies. The fluidized bead surfaces may also be detachable for facilitating infection control procedures.